Vaughan Merrick 4/5/11
Block 8
What type of reaction is 1a?- Double Replacement
What type of reaction is 1b?- Corrosion
What do you think reaction 2 and 3 are? - Synthesis
- What is hypoxia?
Hypoxia is a condition in which the level of dissolved oxygen is too low to sustain animal life. This usually occurs when dissolved oxygen levels are below 2 milligrams per liter.
- When does hypoxia reach its highest levels in Long Island Sound and in the Gulf of Mexico?
Hypoxia reaches its highest levels in the Long Island Sound and in the Gulf of Mexico when the colder water separates from the warmer water and stays along the bottom layers of the water. When this occurs, the growth of phytoplankton and bacteria increase thus using up more oxygen and creating hypoxia in these bodies of water.
- What causes hypoxia?
The causes of hypoxia include the build up of nutrients in the water and the stratification of the water. When fresh water enters the ocean, the growth of phytoplankton occurs from the increase in nutrients that fresh water has. Once these phytoplankton die, they fall to the ocean floor, where they are decomposed by bacteria. These bacteria use the dissolved oxygen and do not recycle it, thus resulting in decreased dissolved oxygen levels. In addition, due to changing temperatures and salinity, the cool, dense water separates from the warm water and stays near the surface. The bottom layer is then isolated and oxygen cannot normally resupply. Thus dissolved oxygen is depleted and hypoxia occurs.
- Research the sources of high levels of nitrate ions in water bodies.
The sources of high levels of nitrate ions in water bodies occur from fertilizer, decaying plants and manure from animals. The nitrate from fertilizer makes its way into groundwater through irrigation and rain. The groundwater can enter bodies of water through small rivers and deltas that feed directly into large bodies of water. In addition, other human activities such as decaying plants and farming are increasing nitrate levels because of the manure that releases nitrate when it decomposes into the soil. Our modern farming techniques that use fertilizers to grow grass for cows have a negative effects on water bodies because of the increased levels of nitrate.
- What are “safe levels” of nitrate in drinking water and what are the effects on humans of drinking water with high levels of nitrate ion?
The “safe levels” of nitrate as reported by the U.S. Environmental Protection Agency are drinking water that contains less than 45 milligrams per liter of nitrate. This figure can also be reported in the units parts per million. The effect of high nitrate in drinking water is a condition called methemoglobinemia or blue baby syndrome. This disease occurs mainly in infants under six months old and causes and increases in the amount of bacteria that convert nitrate (NO3) into nitrite (NO2). Once this nitrite is absorbed into the bloodstream, it is changed into methemoglobin, which does not carry oxygen well. This results in an oxygen deficiency to vital organs in your body.
Url Citations:
http://toxics.usgs.gov/definitions/hypoxia.html
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